I just purchased a set of axioms, 80's, a 150, and M22's. I love the sound, however, my tweeters buzz like there are 200 bees inside them, even when the receiver is muted at -64 dB's. I am running a parasound 855A amp, with bettercable interconnects. I am using an HK AVR45 as a preamp. The speakers don't buzz when I run the wire directly to the receiver. Where am I going wrong here? I don't feel as though any of my components are exactly cheap... The speakers I was running before in the same exact configuration did not buzz like this.

If the speakers do not buzz when hooked to the receiver (assuming you used the same speaker wire to do this) then it is an electrical problem from the pre-amp to the main amp or the main amp itself. This sort of thing is almost always the interconnects but I must admit that would normally isolate the problem to just one channel (unlikely both interconnects have a problem). Another strong possibility is the pre amp and the main amp need to be isolated from each other. If you have one on top of the other currently, I would suggest separating them a bit and see if it affects the noise you are getting.

1) When you connected the Axioms directly to the H/K, was the H/K configured to be both a Pre and Power amp?
2)If you have the HK (preamp) connected to the Parasound(amp) with the Axioms(speakers) attached to the Parasouns(amp) - you mention the buzz is there even with the preamp volume turned down?
3) are you connecting both old and new speakers with the same speaker cable?

I suspect that you have a problem with a ground. try this:
- leave the amp connected to the Axioms,
- disconnect the interconnects from the preamp, at the amp input, BOTH CHANNELS!
- check if the buzz is present.
This test should have No preamp, No interconnects, No source = only amp, speaker cables, speakers
What I suspect is a ground potential problem between the amp and preamp. As Ian mentions, an interconnect can cause this problem by "electrically connecting" the pre to amp via a cable conductor or shield. It would only take one interconnect in this situation to cause a ground loop that would be present on both channels.

If the amp and speakers do not make a noise, that is the problem.
If the amp and speakers DO make the noise (with no preamp, or source - amp to speakers only) I believe your amp could be the problem.

Well... I discovered that it is mostly caused from the satellite. When I unplug the coax most of the hum it eliminated. What little is left, I believe stems from a receiver with a 2 pronged power connection connected to an amp with a 3 pronged power connection. Unfortuneately, most of the filters being made today do not work with satellite because the satellite receives its power through the coax. I've placed a "cheater" plug on the amp to get rid of the ground prong and that seems to help. This of course isn't a permanent solution and I need to look into how my satellite system is grounded.

Hum is almost always ground related. There can be instances where ac or dc is affecting the sound, and I would suggest looking at the electrical outlets you have these plugged into as well. Are the polarities of the plug(s) correct? Are they on the same circuit breaker? If so, are they properly grounded electricaly? If not, are they proper connected at the electrical panel? It is not a mandate that each piece (cd, receiver, etc) have 3 prongs on the cord. It is required that the polarities be correct for the electrical outlet, especially if there are 2 prongs on a polarized plug.

Also, I would suggest anyone who is considering a serious system, HT or music to make sure the electrical cirsuits are properly installed. If you can have them installed, isolated circuits are definitely the way to go. Power bars and the like are really stop gap measures.